A CARP-1 functional mimetic compound is synergistic with BRAF-targeting in non-small cell lung cancers

// Vino T. Cheriyan 1, 2 , Hashem Alsaab 5, 7 , Sreeja Sekhar 1, 2 , Jaganathan Venkatesh 1, 2 , Arindam Mondal 6 , Imran Vhora 6 , Samaresh Sau 5 , Magesh Muthu 1, 2, 8 , Lisa A. Polin 2, 4 , Edi Levi 1, 3 , Gerold Bepler 2 , Arun K. Iyer 4, 5 , Mandip Singh 6 and Arun K. Rishi 1, 2, 4 1 John D. Dingell VA Medical Center, Detroit, MI, 48201, USA 2 Department of Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University, School of Medicine, Detroit, MI, 48201, USA 3 Department of Pathology, Wayne State University, School of Medicine, Detroit, MI, 48201, USA 4 Molecular Therapeutics Program, Barbara Ann Karmanos Cancer Institute, Wayne State University, School of Medicine, Detroit, MI, 48201, USA 5 Use-inspired Biomaterials and Integrated Nano Delivery (U-BiND) Systems Laboratory Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA 6 College of Pharmacy and Pharmaceutical Sciences, Florida AM TKIs; CFM; CARP-1/CCAR1; B-Raf-inhibitors Received: January 03, 2018      Accepted: May 15, 2018      Published: July 03, 2018 ABSTRACT Non-small cell lung cancers (NSCLC) account for 85% of all lung cancers, and the epidermal growth factor receptor (EGFR) is highly expressed or activated in many NSCLC that permit use of EGFR tyrosine kinase inhibitors (TKIs) as frontline therapies. Resistance to EGFR TKIs eventually develops that necessitates development of improved and effective therapeutics. CARP-1/CCAR1 is an effector of apoptosis by Doxorubicin, Etoposide, or Gefitinib, while CARP-1 functional mimetic (CFM) compounds bind with CARP-1, and stimulate CARP-1 expression and apoptosis. To test whether CFMs would inhibit TKI-resistant NSCLCs, we first generated and characterized TKI-resistant NSCLC cells. The GI 50 dose of Erlotinib for parental and Erlotinib-resistant HCC827 cells was ~0.1 μM and ≥15 μM, respectively. While Rociletinib or Ocimertinib inhibited the parental H1975 cells with GI 50 doses of ≤0.18 μM, the Ocimertinib-resistant pools of H1975 cells had a GI 50 dose of ~12 μM. The GI 50 dose for Rociletinib-resistant H1975 sublines ranged from 4.5-8.0 μM. CFM-4 and its novel analog CFM-4.16 attenuated growth of the parental and TKI-resistant NSCLC cells. CFMs activated p38/JNKs, inhibited oncogenic cMet and Akt kinases, while CARP-1 depletion blocked NSCLC cell growth inhibition by CFM-4.16 or Erlotinib. CFM-4.16 was synergistic with B-Raf-targeting in NSCLC, triple-negative breast cancer, and renal cancer cells. A nano-lipid formulation (NLF) of CFM-4.16 in combination with Sorafenib elicited a superior growth inhibition of xenografted tumors derived from Rociletinib-resistant H1975 NSCLC cells in part by stimulating CARP-1 and apoptosis. These findings support therapeutic potential of CFM-4.16 together with B-Raf targeting in treatment of TKI-resistant NSCLCs.